Prominent among the automatic data processing equipment normally used in banking institutions and the like is the document reader sorter which provides for the automatic machine reading of data recorded on documents such as bank checks, and for the automatic sorting of the documents into a plurality of document pockets, quantities of the documents being manually placed in a document hopper from which they are individually fed at high speed along a document transport guideway past a read station to a selected one of the plurality of pockets. The machine reading of the data recorded on the individual documents is accomplished by means of one or more MICR or OCR read heads disposed at the read station, and sorting of the documents is generally accomplished automatically as a by-product of the machine reading function, data encoded in a given field on the face of the document being readably interpreted to select the particular pockets into which the documents are to be sorted.
The operation of a typical document reader sorter in which MICR encoded checks are automatically processed may be described with reference to FIG. 1. In such reader sorters, the encoded checks containing ferromagnetic indicia are placed in a hopper compartment generally designated at 3 and individually fed by a driven belt 5 into a guideway 7 to the control of a driven burst roller 9, the driven burst roller serving to activate the individual checks at high speed along a guideway 11 to the control of a driven transport drum 13, the transport drum 13 activating the individual checks through a read station and along a guideway 15 to a plurality of selectable pockets generally designated at 17. A plurality of motors 18 are utilized for rotating the belt 5, the burst roller 9 and the transport drum 13. Rotatable rollers 19 are disposed along the guideways 7, 11 and 15 to provide free movement of the checks therealong, and a plurality of Beam-o-Lights 21 are disposed along the guideways to provide effective monitoring of check movement and to shut the apparatus down should the free flow of checks be interrupted. As the individual checks are transported around the transport drum 13, the ferromagnetic indicia encoded thereon is magnetized by a magnetizing head 23, and the magnetized indicia read by a read head 25, such magnetizing and reading being accomplished as the individual checks are transported at high speed around the transport drum 13 and into the guideway 15.
The hopper compartment 3 in document reader sorters of this type is generally provided with a pressure flag 27 effective for urging the documents in the hopper, and particularly the leading document therein, into frictional contact with the feed belt 5. The feed belt 5 is typically made of cork and is disposed around a driven feed pulley 29 having a rubber tire (not shown) disposed around its periphery, and a spring-loaded idler pulley 31, the cork belt and rubber tire of the feed pulley providing a coefficient of friction considerably greater than the coefficient of friction as between the documents themselves and between the documents and a driven separator belt that is not shown in FIG. 1 but generally disposed in the area designated 33 in the drawing.
Although document feeders such as that illustrated in FIG. 1 and briefly described supra have proven effective for feeding documents at a speed of from 150 to 200 inches per second, and for achieving a document throughput for the reader sorter of from 1,500 to 2,000 6-inch documents per minute, they have been found to be relatively unreliable when used in reader sorters where a feeding speed of from 300 to 600 inches per second is required to maintain a document throughput of from 3,000 to 5,000 documents per minute, such increased document throughput being regarded as essential goals in the development of future generation document reader sorters. Of particular concern in the use of such known document feeders in higher speed reader sorters is the susceptibility of the cork belt 5 and the rubber-tired feed pulley 29 to experience excessive wear, particularly when subjected to the force that has heretofore been applied by the pressure flag 27, the occurrence of wear in the rubber tire resulting in undesirable slippage in document feeding.